In the picture below, the 3 charges Q1, Q2 and Q3 are located at positions (-a,0), (a,0) and (0,-d) respectively. (The origin is the point halfway between Q1 and Q2.)
a) Consider the special case where Q1, Q3 greater than zero and Q2 = -Q1.
Select true or false for each statement.
True: If Q3 is released from rest, it will initially accelerate to the right.
False: The external work done to bring these charges to this configuration (from infinity) was positive.
False: The electric field at the origin points solely in the positive y direction.
True: The electric potential at the origin equals Q3/(4πε0d).
(Recall that k = 1/(4πε0))
True: The electric potential at any point along the y-axis is positive.
False: The force on Q3 due to the other two charges is zero.
True: The work required to move Q3 from its present position to the origin is zero.
b) In the previous problem, let Q1=1.60 μC, Q2=-3.20 μC, and Q3=3.30 μC. (Note that Q1 and Q2 are different now.) The distances are a=1.20 cm and d=2.80 cm.
Calculate the potential energy of the charge configuration
Start with charges at infinity, and calculate the work required to bring them to the final configuration, one at a time. Don't forget to convert cm to m.